scholarly journals Cerebellar anodal tDCS increases implicit visuomotor remapping when strategic re-aiming is suppressed

2016 ◽  
Author(s):  
Li-Ann Leow ◽  
Welber Marinovic ◽  
Stephan Riek ◽  
Timothy J Carroll
Keyword(s):  
Visual Feedback ◽  
Explicit Knowledge ◽  
Hand Position ◽  
Sensorimotor Adaptation ◽  
Anodal Tdcs ◽  
Movement Initiation ◽  
Implicit Processes ◽  
Target Presentation ◽  
Explicit Processes ◽  
The Right

AbstractThe cerebellum is known to be critically involved in sensorimotor adaptation. Changes in cerebellar function alter behaviour when compensating for sensorimotor perturbations, as shown by non-invasive stimulation of the cerebellum and studies involving patients with cerebellar degeneration. It is known, 24 however, that behavioural responses to sensorimotor perturbations reflect both explicit processes (such as volitional aiming to one side of a target to counteract a rotation of visual feedback) and implicit, error-driven updating of sensorimotor maps. The contribution of the cerebellum to these explicit and implicit processes remains unclear. Here, we examined the role of the cerebellum in sensorimotor adaptation to a 30° rotation of visual feedback of hand position during target-reaching, when the capacity to use explicit processes was manipulated by controlling movement preparation times. Explicit re-aiming was suppressed in one condition by requiring subjects to initiate their movements within 300ms of target presentation, and permitted in another condition by requiring subjects to wait approximately 1050ms after target presentation before movement initiation. Similar to previous work, applying anodal transcranial direct current stimulation (tDCS; 1.5mA) to the right cerebellum during adaptation resulted in faster compensation for errors imposed by the rotation. After exposure to the rotation, we evaluated implicit remapping in no-feedback trials after providing participants with explicit knowledge that the rotation had been removed. Crucially, movements were more adapted in these no-feedback trials following cerebellar anodal tDCS than after sham stimulation in both long and short preparation groups. This suggests that cerebellar anodal tDCS increased implicit remapping during sensorimotor adaptation irrespective of preparation time constraints. This work shows that the cerebellum is critical in the formation of new visuomotor maps that correct perturbations in sensory feedback, both when explicit processes are suppressed and when allowed during sensorimotor adaptation.

scholarly journals Explicit knowledge and learning in SLA

AILA Review ◽  
2010 ◽  
Vol 23 ◽  
pp. 7-29 ◽  
Author(s):  
Karen Roehr
Keyword(s):  
Cognitive Linguistics ◽  
Explicit Knowledge ◽  
Human Mind ◽  
Implicit Processes ◽  
Starting Point ◽  
Explicit Processes ◽  
L2 Development ◽  
Explicit Processing ◽  
Implicit And Explicit ◽  
Explicit And Implicit Knowledge

SLA researchers agree that explicit knowledge and learning play an important role in adult L2 development. In the field of cognitive linguistics, it has been proposed that implicit and explicit knowledge differ in terms of their internal category structure and the processing mechanisms that operate on their representation in the human mind. It has been hypothesized that linguistic constructions which are captured easily by metalinguistic descriptions can be learned successfully through explicit processes, resulting in accurate use. However, increased accuracy of use arising from greater reliance on explicit processing may lead to decreased fluency. Taking these hypotheses as a starting point, I present a case study of an adult L2 learner whose development of oral proficiency was tracked over 17 months. Findings indicate that explicit knowledge and learning have benefits as well as limitations. Use of metalinguistic tools was associated with increased accuracy; moreover, there was no obvious trade-off between accuracy and fluency. At the same time, resource-intensive explicit processing may impose too great a cognitive load in certain circumstances, apparently resulting in implicit processes taking over. I conclude that explicit and implicit knowledge and learning should be considered together in order to gain a full understanding of L2 development.

scholarly journals The primary motor cortex is critical for the retention of implicit sensorimotor adaptation

2016 ◽  
Author(s):  
Li-Ann Leow ◽  
Welber Marinovic ◽  
Timothy J Carroll ◽  
Stephan Riek
Keyword(s):  
Motor Cortex ◽  
Implicit Learning ◽  
Visual Feedback ◽  
Primary Motor Cortex ◽  
Single Pulse ◽  
Sensorimotor Adaptation ◽  
List Type ◽  
Movement Preparation ◽  
Implicit Processes

AbstractSensorimotor adaptation, or adaptation of movements to external perturbations, is thought to involve the primary motor cortex (M1). In addition to implicit error-driven remapping, explicit re-aiming strategies also contribute to sensorimotor adaptation. However, no studies to date have examined the role of M1 in implicit learning in isolation from explicit strategies. Because the application of explicit strategies requires time, it is possible to emphasise implicit learning by controlling the time available to prepare movement. Here, we examined the role of M1’s role in implicit adaptation to rotated visual feedback whilst suppressing the use of explicit re-aiming strategies by limiting movement preparation times to less than 350ms. Perturbing M1 activity via single-pulse TMS during adaptation to a 30 ° rotation of visual feedback did not alter the rate or extent of error compensation, but elicited poorer retention in post-adaptation trials with no perturbation. This work shows that M1 is critical in the retention of new visuomotor maps as a result of implicit adaptation to a perturbation in sensory feedback when strategic error correction processes are suppressed.HighlightsAdaptation of movements to perturbations occurs through explicit and implicit processes.Here, explicit strategies were suppressed by shortening movement preparation time.Perturbing motor cortex (M1) with TMS selectively impaired retention but not acquisition of sensorimotor adaptation.M1 plays a crucial role in retention of sensorimotor adaptation obtained via implicit learning.

scholarly journals Use of explicit processes during a visually guided locomotor learning task predicts 24-hour retention after stroke

2020 ◽  
Author(s):  
Margaret A French ◽  
Susanne M. Morton ◽  
Darcy S. Reisman
Keyword(s):  
Visual Feedback ◽  
Step Length ◽  
Learning Task ◽  
Learning Processes ◽  
Healthy Adults ◽  
Stroke Survivors ◽  
Visually Guided ◽  
Implicit Processes ◽  
Explicit Processes ◽  
Implicit And Explicit

Implicit and explicit processes can occur within a single locomotor learning task. The combination of these learning processes may impact how individuals acquire/retain the task. Because these learning processes rely on distinct neural pathways, neurologic conditions may selectively impact the processes that occur, thus, impacting learning and retention. Thus, our purpose was to examine the contribution of implicit and explicit processes during a visually guided walking task and characterize the relationship between explicit processes and performance/retention in stroke survivors and age-matched healthy adults. Twenty chronic stroke survivors and twenty healthy adults participated in a 2-day treadmill study. Day 1 included Baseline, Acquisition1, Catch, Acquisition2, and Immediate Retention phases and Day 2 included 24-hour Retention. During acquisition phases, subjects learned to take a longer step with one leg through distorted visual feedback. During Catch and retention phases, visual feedback was removed and subjects were instructed to walk normally (Catch) or how they walked during the acquisition phases (retention). Change in step length from Baseline to Catch represented implicit processes. Change in step length from Catch to the end of Acquisition2 represented explicit processes. A mixed ANOVA found no difference in the type of learning between groups (p=0.74). There was a significant relationship between explicit processes and 24-hour retention in stroke survivors (r=0.47, p=0.04), but not in healthy adults (r=0.34, p=0.15). These results suggest that stroke may not affect the underlying learning mechanisms used during locomotor learning, but that these mechanisms impact how well stroke survivors retain the new walking pattern.

scholarly journals Continuous Reports of Sensed Hand Position During Sensorimotor Adaptation

2020 ◽  
Author(s):  
Jonathan S. Tsay ◽  
Darius E. Parvin ◽  
Richard B. Ivry
Keyword(s):  
Visual Feedback ◽  
Subjective Experience ◽  
Motor Behavior ◽  
Hand Position ◽  
Sensorimotor Adaptation ◽  
Reaching Movement ◽  
Fixed Angle ◽  
Trial Basis ◽  
Subjective Reports ◽  
Visual Perturbation

ABSTRACTSensorimotor learning entails multiple learning processes, some volitional and explicit, and others automatic and implicit. A new method to isolate implicit adaptation involves the use of a “clamped” visual perturbation in which, during a reaching movement, visual feedback is limited to a cursor that follows an invariant trajectory, offset from the target by a fixed angle. Despite full awareness that the cursor movement is not contingent on their behavior, as well as explicit instructions to ignore the cursor, systematic changes in motor behavior are observed, and these changes have the signatures of implicit adaptation observed in studies using classic visuomotor perturbations. While it is clear that the response to clamped feedback occurs automatically, it remains unknown if the adjustments in behavior remain outside the participant’s awareness. To address this question, we used the clamp method and directly probed awareness by asking participants to report their hand position after each reach. As expected, we observed robust deviations in hand angle away from the target (average of ∼18°). The hand reports also showed systematic deviations over the course of adaptation, initially attracted towards the visual feedback and then in the opposite direction, paralleling the shift in hand position. However, these effects were subtle (∼2° at asymptote), with the hand reports dominated by a feedforward signal associated with the motor intent yet modulated in a limited way by feedback sources. These results confirm that adaptation in response to a visual perturbation is not only automatic, but also largely implicit.NEWS AND NOTEWORTHYSensorimotor adaptation operates in an obligatory manner. Qualitatively, subjective reports obtained after adaptation demonstrate that, in many conditions, participants are unaware of significant changes in behavior. In the present study, we quantified participants’ awareness of adaptation by obtaining reports of hand position on a trial-by-trial basis. The results confirm that participants are largely unaware of adaptation, but also reveal the subtle influence of feedback on their subjective experience.

Patterns of Implicit Learning Below the Level of Conscious Knowledge

2010 ◽  
Vol 24 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Juliana Yordanova ◽  
Rolf Verleger ◽  
Ullrich Wagner ◽  
Vasil Kolev
Keyword(s):  
Implicit Learning ◽  
Explicit Knowledge ◽  
Implicit Knowledge ◽  
Knowledge Generation ◽  
Sleep Stages ◽  
Implicit Processing ◽  
Implicit Processes ◽  
Late Night ◽  
On Line ◽  
On Line Learning

The objective of the present study was to evaluate patterns of implicit processing in a task where the acquisition of explicit and implicit knowledge occurs simultaneously. The number reduction task (NRT) was used as having two levels of organization, overt and covert, where the covert level of processing is associated with implicit associative and implicit procedural learning. One aim was to compare these two types of implicit processes in the NRT when sleep was or was not introduced between initial formation of task representations and subsequent NRT processing. To assess the effects of different sleep stages, two sleep groups (early- and late-night groups) were used where initial training of the task was separated from subsequent retest by 3 h full of predominantly slow wave sleep (SWS) or rapid eye movement (REM) sleep. In two no-sleep groups, no interval was introduced between initial and subsequent NRT performance. A second aim was to evaluate the interaction between procedural and associative implicit learning in the NRT. Implicit associative learning was measured by the difference between the speed of responses that could or could not be predicted by the covert abstract regularity of the task. Implicit procedural on-line learning was measured by the practice-based increased speed of performance with time on task. Major results indicated that late-night sleep produced a substantial facilitation of implicit associations without modifying individual ability for explicit knowledge generation or for procedural on-line learning. This was evidenced by the higher rate of subjects who gained implicit knowledge of abstract task structure in the late-night group relative to the early-night and no-sleep groups. Independently of sleep, gain of implicit associative knowledge was accompanied by a relative slowing of responses to unpredictable items suggesting reciprocal interactions between associative and motor procedural processes within the implicit system. These observations provide evidence for the separability and interactions of different patterns of processing within implicit memory.

scholarly journals Effects of tDCS during inhibitory control training on performance and PTSD, aggression and anxiety symptoms: a randomized-controlled trial in a military sample

2021 ◽  
pp. 1-11
Author(s):  
Fenne M. Smits ◽  
Elbert Geuze ◽  
Dennis J. L. G. Schutter ◽  
Jack van Honk ◽  
Thomas E. Gladwin
Keyword(s):  
Randomized Controlled Trial ◽  
Inhibitory Control ◽  
Response Inhibition ◽  
Clinical Sample ◽  
Controlled Trial ◽  
Anodal Tdcs ◽  
Randomized Controlled ◽  
Impulsive Aggression ◽  
The Right ◽  
Inhibition Training

Abstract Background Post-traumatic stress disorder (PTSD), anxiety, and impulsive aggression are linked to transdiagnostic neurocognitive deficits. This includes impaired inhibitory control over inappropriate responses. Prior studies showed that inhibitory control can be improved by modulating the right inferior frontal gyrus (IFG) with transcranial direct current stimulation (tDCS) in combination with inhibitory control training. However, its clinical potential remains unclear. We therefore aimed to replicate a tDCS-enhanced inhibitory control training in a clinical sample and test whether this reduces stress-related mental health symptoms. Methods In a preregistered double-blind randomized-controlled trial, 100 active-duty military personnel and post-active veterans with PTSD, anxiety, or impulsive aggression symptoms underwent a 5-session intervention where a stop-signal response inhibition training was combined with anodal tDCS over the right IFG for 20 min at 1.25 mA. Inhibitory control was evaluated with the emotional go/no-go task and implicit association test. Stress-related symptoms were assessed by self-report at baseline, post-intervention, and after 3-months and 1-year follow-ups. Results Active relative to sham tDCS neither influenced performance during inhibitory control training nor on assessment tasks, and did also not significantly influence self-reported symptoms of PTSD, anxiety, impulsive aggression, or depression at post-assessment or follow-up. Conclusions Our results do not support the idea that anodal tDCS over the right IFG at 1.25 mA enhances response inhibition training in a clinical sample, or that this tDCS-training combination can reduce stress-related symptoms. Applying different tDCS parameters or combining tDCS with more challenging tasks might provide better conditions to modulate cognitive functioning and stress-related symptoms.

scholarly journals VALENCE OF PREDICATES IN THE ACTIVE-PASSIVE TRANSFORMATION IN GERMAN AND UKRAINIAN

2020 ◽  
pp. 77-82
Author(s):  
Tsymbalista L.R.
Keyword(s):  
Sampling Method ◽  
Syntactic Structure ◽  
Hand Position ◽  
Continuous Sampling ◽  
Left Hand ◽  
Decisive Effect ◽  
Modern Fiction ◽  
The Subject ◽  
The Right

Валентність предиката має вирішальний вплив на структуру речення. Хоча активний і пасивний варіанти речення опису-ють одну й ту ж ситуацію, предикат проходить крізь трансформацію, яка тісно пов’язана з явищем валентності. У цій статті проаналізовано валентність предиката та її вплив на цю трансформацію у німецькій та українській мовах на прикладах із сучасної літератури.Мета. Метою статті є порівняння трансформації «актив – пасив» у німецькій та українській мовах та опис ролі валентності у цьому процесі.Методи. Для проведення дослідження було зібрано методом суцільної вибірки приклади пасивних конструкцій із сучас-них художніх текстів німецькою та українською мовами, які опісля було оброблено та проаналізовано з використанням типо-логічного, зіставного, описового методів, а також методу моделювання.Валентність предиката проявляється у його здатності формувати зв’язки з іншими елементами в реченні та дає змогу передбачити додаткові позиції у синтаксичній структурі речення, які можуть бути заповнені обов’язковими чи факультатив-ними компонентами. Для предиката властиві два типи валентності, які залежать від позиції поширювачів у реченні. Якщо лівобічну позицію переважно пов’язують із суб’єктом, то правобічна зазвичай стосується актантів з об’єктним, адресатним, локативним чи інструментальним значеннями.Результати. Зважаючи на те, що одна й та ж функція пасивних конструкцій у німецькій та українській мовах реалізується різними формами, валентні зміни у кожній з конструкцій мають свої особливості. Спільною рисою цих перетворень виступає зменшення облігаторних актантів на одну одиницю, яка може бути заповнена факультативно у разі комунікативної потреби у інформації про виконавця дії.Висновки. Можна зробити висновок, що валентність предиката є багатогранним феноменом, що підлягає впливу не лише формально-граматичних, а й семантико-синтаксичних чинників, а також мовленнєвої ситуації загалом. Відповідно, змін у валентності предикатів протягом трансформації з активу у пасив не можна уникнути. The valence of the predicate has a decisive effect on the structure of the sentence. Although the active and passive variant of the sentence describes the same situation, the predicate goes through a transformation that also has to do with valence. This article analyzes the valency of the predicate and its influence on such transformation in German and Ukrainian based on the examples from modern literature.Purpose. The purpose of the article is to compare the active-passive transformation in German and Ukrainian and to describe the role of valence in this process.Methods. For the research, we collected the examples of passive constructions from modern fiction in German and Ukrainian using the continuous sampling method, which were then processed and analyzed using typological, comparative, descriptive methods as well as the modelling method.The valence of the predicate verb shows in its ability to connect with other sentence elements and enables the prediction of the additional positions in the syntactic structure of the sentence, which can be supplemented by mandatory or optional components. The predicate is characterized by two types of valence, which depend on the position of the fillers in the sentence: the left-hand position is mainly connected the subject of the utterance, and the right-hand position has to do with actants which define object, addressee, location or have instrumental meaning.Results. Due to the fact that the same function of passive constructions in German and Ukrainian is realized in different forms, the valence changes in each of the constructions have their own features. A common feature of these transformations is the reduction of obligatory actants by one unit, which can be filled in optionally in case of communicative need for information about the performer of the action.Conclusions. We reach the conclusion that the valence of the predicate is a multilevel phenomenon that is influenced not only by formal grammatical but also by semantic and syntactic factors as well as the language situation in general. Accordingly, changes in the valence of predicates during the active-passive transformation are inevitable.

The Spatial Dependency of Shoulder Muscle Demands for Seated Lateral Hand Force Exertions

2014 ◽  
Vol 30 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Alison C. McDonald ◽  
Elora C. Brenneman ◽  
Alan C. Cudlip ◽  
Clark R. Dickerson
Keyword(s):  
Repeated Measures ◽  
Muscle Activation ◽  
Three Dimensional ◽  
Emg Activity ◽  
Hand Position ◽  
Individual Muscle ◽  
Repeated Measures Analysis ◽  
Spatial Parameters ◽  
Shoulder Complex ◽  
The Right

As the modern workplace is dominated by submaximal repetitive tasks, knowledge of the effect of task location is important to ensure workers are unexposed to potentially injurious demands imposed by repetitive work in awkward or sustained postures. The purpose of this investigation was to develop a three-dimensional spatial map of the muscle activity for the right upper extremity during laterally directed submaximal force exertions. Electromyographic (EMG) activity was recorded from fourteen muscles surrounding the shoulder complex as the participants exerted 40N of force in two directions (leftward, rightward) at 70 defined locations. Hand position in both push directions strongly influenced total and certain individual muscle demands as identified by repeated measures analysis of variance (P< .001). During rightward exertions individual muscle activation varied from 1 to 21% MVE and during leftward exertions it varied from 1 to 27% MVE with hand location. Continuous prediction equations for muscular demands based on three-dimensional spatial parameters were created with explained variance ranging from 25 to 73%. The study provides novel information for evaluating existing and proactive workplace designs, and may help identify preferred geometric placements of lateral exertions in occupational settings to lower muscular demands, potentially mitigating fatigue and associated musculoskeletal risks.

scholarly journals Continuous reports of sensed hand position during sensorimotor adaptation

2020 ◽  
Vol 124 (4) ◽  
pp. 1122-1130 ◽  
Author(s):  
Jonathan S. Tsay ◽  
Darius E. Parvin ◽  
Richard B. Ivry
Keyword(s):  
Subjective Experience ◽  
Hand Position ◽  
Sensorimotor Adaptation ◽  
Adaptive Changes ◽  
Trial Basis ◽  
Subjective Reports

Sensorimotor adaptation operates in an obligatory manner. Qualitatively, subjective reports obtained after adaptation demonstrate that, in many conditions, participants are unaware of significant changes in behavior. In the present study, we quantified participants’ sensitivity to these adaptive changes by obtaining reports of hand position on a trial-by-trial basis. The results confirm that participants are largely unaware of adaptation but also reveal the subtle influence of feedback on their subjective experience.

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